Polyurethane Composite Material and Process of Preparing Same

ABSTRACT

The present invention relates to a polyurethane composite material, comprising a polyurethane resin matrix prepared from a polyurethane composition, and a reinforcement material, wherein the polyurethane composition comprises: A) an isocyanate component comprising one or more organic polyisocyanates; B) an isocyanate-reactive component comprising: b1) one or more organic polyols having an amount of 21-60 wt. % based on 100% by weight of the polyurethane composition; b2) one or more (meth)acrylates comprising hydroxyl groups; and C) a radical reaction initiator; wherein the polyurethane resin matrix is prepared under such reaction conditions that the polyurethane composition undergoes addition polymerization reaction of isocyanate groups and hydroxyl groups and radical polymerization reaction simultaneously. The present invention further relates to the preparation process of the polyurethane composite material.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application claiming priority under35 U.S.C. § 120 to U.S. application Ser. No. 15/303,185, which was filedon Oct. 10, 2016 under 35 U.S.C. § 371, and which claims priority toPCT/EP2015/057541, which was filed on Apr. 8, 2015, and which claimspriority to Chinese Patent Application No. CN 201410840608.5, filed Dec.23, 2014 and Chinese Patent Application No. CN 201410156175.1, filedApr. 10, 2014, the contents of each of which are incorporated byreference into this specification.

TECHNICAL FIELD

The invention relates to a polyurethane composite material comprising apolyurethane resin matrix and a reinforcement material and a process ofpreparing the same. Particularly, the polyurethane resin matrix isprepared under such reaction conditions that a polyurethane compositionundergoes addition polymerization reaction of isocyanate groups andhydroxyl groups and radical polymerization reaction simultaneously.

BACKGROUND ART

A fiber reinforced polyurethane composite material is composed of two ormore different physical phases, wherein a fiber is distributed in acontinuous phase of a polyurethane resin matrix. As compared with aconventional material, a fiber reinforced polyurethane compositematerial features light weight, good corrosion resistance, hightoughness and high processability. However, as a traditionalpolyurethane system has a short gel time or pot life, it is quitedemanding on an application process. Moreover, a polyurethane resinprepared under process conditions for preparing a fiber reinforced highmolecular composite material still has insufficient mechanicalproperties and strength.

Patent Application WO91/18933 discloses a resin composition for resininjection molding, comprising: a component comprising an unsaturatedbond and an active group which can react with isocyanate; an ethylenicmonomer which can undergo radical polymerization reaction with the abovecomponent; an isocyanate comprising an isocyanate group having afunctionality of greater than 1.75; and a compound comprising two ormore isocyanate-reactive groups or vinyl unsaturated groups, wherein thecompound has an amount of 2-20% and a molecular weight of 500-3000. Thisresin composition may be made into a polyurethane composite material byresin injection molding, resin transfer molding, etc.

Patent Application WO2002/083758 discloses a LPA hybrid, comprising: afirst component comprising at least one ethylenic bond and an isocyanatereactive group; a second component which is an ethylenically unsaturatedmonomer that can react with the first component by means of radicalpolymerization; a third component consisting of a polyisocyanate thatcan react with the first component by means of polyurethane reaction andthat has an average functionality of at least 1.75; a fourth componentwhich is a catalyst for the radical polymerization; and a thermoplasticpolymer comprising 3-20% of the hybrid and having a molecular weight ofat least 10,000 Dalton.

SUMMARY

One object of the invention is to provide a polyurethane compositematerial, wherein a polyurethane composition for forming a polyurethaneresin matrix has a relatively long gel time or pot life to improveprocessability. In addition, the polyurethane composite materialprepared from this polyurethane composition has good mechanicalproperties.

In one aspect, the invention relates to a polyurethane compositematerial, comprising a polyurethane resin matrix prepared from apolyurethane composition, and a reinforcement material, wherein thepolyurethane composition comprises:

-   -   A) an isocyanate component comprising one or more organic        polyisocyanates;    -   B) an isocyanate-reactive component comprising:    -   b1) one or more organic polyols having an amount of 21-60 wt. %        based on 100% by weight of the polyurethane composition;    -   b2) one or more compounds having structure (I)

-   -   wherein R₁ is selected from hydrogen, methyl or ethyl; R₂ is        selected from alkylene groups having 2-6 carbon atoms,        2,2-bis(4-phenylene) propane, 1,4-bis(methylene)benzene,        1,3-bis(methylene)benzene, 1,2-bis(methylene) benzene; n is an        integer selected from 1-6; and    -   C) a radical reaction initiator,    -   wherein the polyurethane resin matrix is prepared under such        reaction conditions that the polyurethane composition undergoes        addition polymerization reaction of isocyanate groups and        hydroxyl groups and radical polymerization reaction        simultaneously.

In an embodiment of the invention, the component b1) is selected fromone or more polyether polyols.

In another embodiment of the invention, the component b2) is selectedfrom the group consisting of hydroxyethyl methacrylate, hydroxypropylmethacrylate, hydroxybutyl methacrylate, hydroxyethyl acrylate,hydroxypropyl acrylate, hydroxybutyl acrylate and combinations thereof.

In still another embodiment of the invention, the organic polyols have afunctionality of 1.7-6 and a hydroxyl number of 150 to 1100 mg KOH/g.Preferably, the polyurethane composite material is prepared by a processselected from compression molding, filament winding, hand lay-upmoulding, spray lay-up moulding and combinations thereof.

In yet another embodiment of the invention, the organic polyols have afunctionality of 1.9-4.5 and a hydroxyl number of 150 to 550 mg KOH/g.Preferably, the polyurethane composite material is prepared by vacuuminfusion process.

In yet another embodiment of the invention, the reinforcement materialis selected from the group consisting of glass fibers, carbon nanotubes,carbon fibers, polyester fibers, natural fibers, aramid fibers, nylonfibers, basalt fibers, boron fibers, silicon carbide fibers, asbestosfibers, whiskers, hard particles, metal fibers and combinations thereof.

In another aspect, the invention relates to a process of preparing apolyurethane composite material which comprises a polyurethane resinmatrix and a reinforcement material, comprising: preparing thepolyurethane resin matrix under such reaction conditions that apolyurethane composition undergoes addition polymerization reaction ofisocyanate groups and hydroxyl groups and radical polymerizationreaction simultaneously, wherein the polyurethane composition comprises:

-   -   A) an isocyanate component comprising one or more organic        polyisocyanates;    -   B) an isocyanate-reactive component comprising:    -   b1) one or more organic polyols having an amount of 21-60 wt. %        based on 100% by weight of the polyurethane composition;    -   b2) one or more compounds having structure (I)

-   -   wherein R₁ is selected from hydrogen, methyl or ethyl; R₂ is        selected from alkylene groups having 2-6 carbon atoms,        2,2-bis(4-phenylene) propane, 1,4-bis(methylene)benzene,        1,3-bis(methylene)benzene, 1,2-bis(methylene) benzene; n is an        integer selected from 1-6; and    -   C) a radical reaction initiator.

In one embodiment of the invention, the component b1) is selected fromone or more polyether polyols.

In another embodiment of the invention, the component b2) is selectedfrom the group consisting of hydroxyethyl methacrylate, hydroxypropylmethacrylate, hydroxybutyl methacrylate, hydroxyethyl acrylate,hydroxypropyl acrylate, hydroxybutyl acrylate and combinations thereof.

In still another embodiment of the invention, the organic polyols have afunctionality of 1.7-6 and a hydroxyl number of 150 to 1100 mg KOH/g.Preferably, the polyurethane composite material is prepared by a processselected from compression molding, filament winding, hand lay-upmoulding, spray lay-up moulding and combinations thereof.

In yet another embodiment of the invention, the organic polyols have afunctionality of 1.9-4.5 and a hydroxyl number of 150 to 550 mg KOH/g.Preferably, the polyurethane composite material is prepared by vacuuminfusion process.

In yet another embodiment of the invention, the reinforcement materialis selected from the group consisting of glass fibers, carbon fibers,polyester fibers, natural fibers, aramid fibers, nylon fibers, basaltfibers, boron fibers, silicon carbide fibers, asbestos fibers, whiskers,hard particles, metal fibers and combinations thereof.

DETAILED DESCRIPTION I. Polyurethane Composite Material

The polyurethane composite material provided according to the inventioncomprises a polyurethane resin matrix prepared from a polyurethanecomposition, and a reinforcement material, wherein the polyurethanecomposition comprises:

-   -   A) an isocyanate component comprising one or more organic        polyisocyanates;    -   B) an isocyanate-reactive component comprising:    -   b1) one or more organic polyols having an amount of 21-60 wt. %        based on 100% by weight of the polyurethane composition;    -   b2) one or more compounds having structure (I)

-   -   wherein R₁ is selected from hydrogen, methyl or ethyl; R₂ is        selected from alkylene groups having 2-6 carbon atoms,        2,2-bis(4-phenylene) propane, 1,4-bis(methylene)benzene,        1,3-bis(methylene)benzene, 1,2-bis(methylene) benzene; n is an        integer selected from 1-6; and    -   C) a radical reaction initiator,    -   wherein the polyurethane resin matrix is prepared under such        reaction conditions that the polyurethane composition undergoes        addition polymerization reaction of isocyanate groups and        hydroxyl groups and radical polymerization reaction        simultaneously.

In an embodiment of the invention, the reinforcement material isselected from fiber reinforcement materials, carbon nanotubes, hardparticles and combinations thereof, more preferably fiber reinforcementmaterials. The reinforcement material has an amount of 5-95 wt. %,preferably 30-85 wt. %, based on 100 wt. % by weight of the polyurethanecomposite material.

When used in the invention, the fiber reinforcement material is notlimited in shape and size. For example, it may be a continuous fiber, afiber net formed by bonding, or a fibrous fabric.

In some embodiments of the invention, the fiber reinforcement materialis selected from the group consisting of glass fibers, carbon fibers,polyester fibers, natural fibers, aramid fibers, nylon fibers, basaltfibers, boron fibers, silicon carbide fibers, asbestos fibers, whiskers,metal fibers and combinations thereof.

In an embodiment of the invention, the organic polyisocyanate may be anyaliphatic, cycloaliphatic or aromatic isocyanate known for preparingpolyurethane. The examples include but are not limited to toluenediisocyanate(TDI), diphenylmethane diisocyanate (MDI), polyphenylmethanepolyisocyanate (pMDI), 1,5-naphthalene diisocyanate (NDI), hexamethylenediisocyanate (HDI), methylcyclohexyl diisocyanate (TDI),4,4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI),p-phenylene diisocyanate (PPDI), xylene diisocyanate (XDI),tetramethyldimethylene diisocyanate (TMXDI), polymers thereof orcompositions thereof. The isocyanate useful for the invention has afunctionality of 2.0-3.5, preferably 2.1-2.9. The viscosity of theisocyanate is preferably 5-700 mPa·s, more preferably 10-300 mPa·s asmeasured at 25° C. according to DIN 53019-1-3.

When used in the invention, the organic polyisocyanate includes dimer,trimer, tetramer or pentamer of isocyanate or a combination thereof.

In a preferred embodiment of the invention, the isocyanate component a)is selected from the group consisting of diphenylmethane diisocyanate(MDI), polyphenylmethane polyisocyanate (pMDI), polymers thereof,prepolymers thereof, and combinations thereof.

A capped isocyanate, which may be prepared by reaction of an excessiveamount of an organic polyisocyanate or a mixture of organicpolyisocyanates with a polyol compound, may also be used as theisocyanate component a). One skilled in the art knows these compoundsand methods for preparing the same.

In an embodiment of the invention, the isocyanate-reactive componentcomprises one or more organic polyols b1). The organic polyol has anamount of 21-60 wt. %, based on 100 wt. % by weight of the polyurethanecomposition. The organic polyols may be those commonly used to preparepolyurethane in the art, including but not limited to polyether polyols,polyethercarbonate polyols, polyester polyols, polycarbonate diols,polymer polyols, vegetable oil based polyols or combinations thereof.

The polyether polyol may be prepared by a known process, for example, byreacting an olefin oxide with a starter in the presence of a catalyst.The catalyst is preferably but not limited to an alkaline hydroxide, analkaline alkoxide, antimony pentachloride, boron trifluoride-diethyletherate or a combination thereof. The olefin oxide is preferably butnot limited to tetrahydrofuran, ethylene oxide, propylene oxide,1,2-butylene oxide, 2,3-butylene oxide, styrene oxide, or a combinationthereof; preferably ethylene oxide and/or propylene oxide. The starteris preferably but not limited to a polyhydroxy compound or a polyaminocompound, wherein the polyhydroxy compound is preferably but not limitedto water, ethylene glycol, 1,2-propanediol, 1,3-propanediol, diethyleneglycol, trimethylolpropane, glycerine, bisphenol A, bisphenol S or acombination thereof, and the polyamino compound is preferably but notlimited to ethylene diamine, propanediamine, butanediamine,hexanediamine, diethylene triamine, toluene diamine or a combinationthereof.

The polyethercarbonate polyol, which may be prepared by addition ofcarbon dioxide and an alkylene oxide compound to a starter comprisingactive hydrogen in the presence of a double metal cyanide catalyst, mayalso be used in the invention.

The polyester polyol is prepared by reaction between a dibasiccarboxylic acid or a dibasic carboxylic anhydride and a polyol. Thedibasic carboxylic acid is preferably but not limited to an aliphaticcarboxylic acid having 2-12 carbons, preferably but not limited tosuccinic acid, malonic acid, glutaric acid, adipic acid, suberic acid,azelaic acid, sebacic acid, dodecyl carboxylic acid, maleic acid,fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, or acombination thereof. The dibasic carboxylic anhydride is preferably butnot limited to phthalic anhydride, tetrachlorophthalic anhydride, maleicanhydride or a combination thereof. The polyol that reacts with thedibasic carboxylic acid or anhydride is preferably but not limited toethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol,dipropylene glycol, 1,3-methylpropanediol, 1,4-butanediol,1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,10-decanediol,glycerine, trimethylolpropane, or a combination thereof. The polyesterpolyol also includes a polyester polyol prepared from a lactone. Thepolyester polyol prepared from a lactone is preferably but not limitedto ε-caprolactone. Preferably, the polyester polyol has a molecularweight of 200-3000 and a functionality of 2-6, preferably 2-4, morepreferably 2-3.

The polycarbonate diol may be prepared by reacting a diol with adihydrocarbyl carbonate or a diaryl carbonate or phosgene. The diol ispreferably but not limited to 1,2-propanediol, 1,3-propanediol,1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol,trioxane diol or a mixture thereof. The dihydrocarbyl or diarylcarbonate is preferably but not limited to diphenyl carbonate.

The polymer polyol may be a polymer modified polyether polyol,preferably a grafted polyether polyol, or a polyether polyol dispersion.The grafted polyether polyol is preferably a styrene and/oracrylonitrile based grafted polyether polyol, wherein the styrene and/oracrylonitrile may be obtained by in situ polymerization of styrene,acrylonitrile, or a mixture of styrene and acrylonitrile, wherein theratio of styrene to acrylonitrile in the mixture of styrene andacrylonitrile is 90:10-10:90, preferably 70:30-30:70. The polymer polyolin the invention may also be castor oil, wood tar or other bio-basedpolyols. The polymer polyether polyol dispersion comprises a dispersionphase, e.g. an inorganic filler, a polyurea, a polyhydrazide, apolyurethane comprising a bonded tertiary amino group and/or melamine.The dispersion phase has an amount of 1-50 wt. %, preferably 1-45 wt. %,based on 100% by weight of the polymer polyether polyol. Preferably, thepolymer polyether polyol has a polymer solid content of 20%-45% based on100% by weight of the polymer polyether and a hydroxyl number of 20-50mgKOH/g.

The vegetable oil based polyol, when used in the invention, includesvegetable oils, vegetable oil polyols or modified products thereof.Vegetable oil is a compound prepared from an unsaturated fatty acid andglycine, or an oil extracted from plant fruits, seeds or embryos, whichis preferably but not limited to peanut oil, bean oil, linseed oil,castor oil, rape seed oil, or palm oil. The vegetable oil polyol is apolyol originated from one or more vegetable oils. A starter forsynthesis of a vegetable oil polyol includes but is not limited tosoybean oil, palm oil, peanut oil, canola oil and castor oil. Hydroxylgroup may be introduced into the starter of a vegetable oil polyol by aprocess such as cracking, oxidation or transesterification, and then thevegetable oil polyol may be prepared using a process known to oneskilled in the art for preparing an organic polyol.

The methods for measuring hydroxyl number are well known to one skilledin the art and are disclosed by, for example, Houben Weyl, Methoden derOrganischen Chemie, vol. XIV/2 Makromolekulare Stoffe, p.17, GeorgThieme Verlag; Stuttgart 1963, which is incorporated herein in itsentity by reference.

Unless otherwise specified, the functionality and the hydroxyl number ofan organic polyol as used herein refer to an average functionality andan average hydroxyl group respectively.

In an embodiment of the invention, the isocyanate-reactive componentfurther comprises one or more compounds b2) having structure (I):

wherein R₁ is selected from hydrogen, methyl or ethyl; R₂ is selectedfrom alkylene groups having 2-6 carbon atoms; and n is an integerselected from 1-6.

In a preferred embodiment of the invention, R₂ is selected fromethylene, trimethylene, tetramethylene, pentamethylene,1-methyl-1,2-ethylene, 2-methyl-1,2-ethylene, 1-ethyl-1,2-ethylene,2-ethyl-1,2-ethylene, 1-methyl-1,3-propylene, 2-methyl -1,3 -propylene,3-methyl-1,3-propylene, 1-ethyl-1,3-propylene, 2-ethyl-1,3-propylene,3-ethyl-1,3-propylene, 1-methyl-1,4-butylene, 2-methyl-1,4-butylene, 3-methy 1-1,4-butylene, 4-methyl-1,4-butylene,2,2-di(4-phenylene)-propane, 1,4-dimethylene benzene, 1,3-dimethylenebenzene, and 1,2-dimethylene benzene.

In a preferred embodiment of the invention, the component b2) isselected from the group consisting of hydroxyethyl methacrylate,hydroxypropyl methacrylate, hydroxybutyl methacrylate, hydroxyethylacrylate, hydroxypropyl acrylate, hydroxybutyl acrylate and combinationsthereof.

The compound of structure (I) may be prepared using a conventionalmethod in the art, e.g. by esterification reaction between (meth)acrylicanhydride, (meth)acrylic acid or (meth)acryloyl halide andHO-(R₂O)_(n)-H. This method is known to one skilled in the art. See, forexample, the description in Chapter 3, Handbook of Polyurethane RawMaterials And Aids (Liu Yijun, published on Apr. 1, 2005) and Chapter 2,Polyurethane Elastomer (Liu Houjun, published in August, 2012), whichare incorporated herein in their entity by reference.

In an embodiment of the invention, the polyurethane composition furthercomprises C) a radical reaction initiator. The radical initiator used inthe invention may be added into the polyol component or the isocyanatecomponent or both. The initiator includes but is not limited toperoxides, persulfides, peroxycarbonates, peroxyboric acid, azocompounds or other suitable radical initiators that can initiate curingof a double bond-containing compound. The examples includetert-butylperoxy isopropyl carbonate, tert-butylperoxy3,5,5-trimethylhexanoate, methyl ethyl ketone peroxide, and cumenehydroperoxide.

Generally, the radical reaction initiator has an amount of 0.1-8 wt. %,based on 100 wt. % by weight of the isocyanate reactive component. Inaddition, there may be present an accelerator, such as cobalt compoundsor amine compounds.

In an embodiment of the invention, the polyurethane composition mayfurther comprise a catalyst for catalyzing the reaction betweenisocyanate group (NCO) and hydroxyl group (OH). A catalyst suitable forpolyurethane reaction is preferably but not limited to an aminecatalyst, an organometallic catalyst or a mixture thereof. The aminecatalyst is preferably but not limited to triethylamine, tributylamine,triethylenediamine, N-ethylmorpholine,N,N,N′,N′-tetramethylethylenediamine, pentamethyldiethylenetriamine,N-methylaniline, N,N-dimethylaniline, or a mixture thereof. Theorganometallic catalyst is preferably but not limited to an organotincompound, e.g. tin (II) acetate, tin (II) octanoate, tin ethylhexanoate,tin laurate, dibutyl tin oxide, dibutyl tin dichloride, dibutyl tindiacetate, dibutyl tin maleate, dioctyl tin diacetate, or a mixturethereof. The catalyst has an amount of 0.001-10 wt. %, based on 100 wt.% by weight of the isocyanate reactive component.

In an embodiment of the invention, for the polyurethane reaction, i.e.the addition polymerization of isocyanate group and hydroxyl group, theisocyanate group may be one carried by the organic polyisocyanate(component A), or one carried by the intermediate product of thereaction between the organic polyisocyanate (component A) and theorganic polyol (component b1) or component b2)); and the hydroxyl groupmay be one carried by the organic polyol (component b1) or componentb2)), or one carried by the intermediate product of the reaction betweenthe organic polyisocyanate (component A) and the organic polyol(component b1) or component b2)).

In an embodiment of the invention, the radical polymerization reactionis an ethylenical addition polymerization, wherein the ethylenical bondmay be one carried by component b2), or one carried by the intermediateproduct of the reaction between component b2) and the organicpolyisocyanate.

In an embodiment of the invention, the polyurethane additionpolymerization (i.e. the addition polymerization of isocyanate group andhydroxyl group) and the radical polymerization occur at the same time.As known to one skilled in the art, reaction conditions may be chosensuitably such that the polyurethane addition polymerization and theradical polymerization undergo in tandem. However, the polyurethanematrix thus prepared is structurally different from the polyurethaneresin matrix prepared by allowing the polyurethane additionpolymerization and the radical polymerization to take placesimultaneously. Consequently, the resulting polyurethane compositematerials have different mechanical properties and processcharacteristics.

In an embodiment of the invention, the polyurethane composition may alsocomprise an aid or an additive, including but not limited to fillers,inner release agents, flame retardants, smoke suppressants, dyes,pigments, antistatic agents, antioxidants, UV stabilizers, diluents,antifoam agents, coupling agents, surface wetting agents, levelingagents, moisture scavengers, catalysts, molecular sieves, thixotropicagents, plasticizers, blowing agents, foam stabilizers, foamhomogenizers, radical reaction suppressants, or combinations thereof,which may be optionally included in isocyanate component A) and/orisocyanate-reactive component B). These ingredients may also be storedseparately as component D). When used to prepare the polyurethanecomposite material, component D) may be mixed with isocyanate componentA) and/or isocyanate-reactive component B) prior to the preparation.

In some embodiments of the invention, the filler is selected from thegroup consisting of aluminum hydroxide, bentonite, fly ash,wollastonite, perlite powder, fly ash floating beads, calcium carbonate,talc powder, mica powder, porcelain clay, fumed silica, expandablemicrospheres, diatomite, pozzuolana, barium sulfate, calcium sulfate,glass microspheres, rock powder, wood flour, wood chips, bamboo flour,bamboo chips, rice grains, chopped crop straw, chopped broomcorn straw,graphite powder, metal powder, recycled powder of thermosettingcomposite materials, plastic particles or powder, or combinationsthereof. The glass microspheres may be solid or hollow.

Inner release agents suitable for the invention include any conventionalrelease agents for manufacturing polyurethane, and examples includelong-chain carboxylic acids, particularly fatty acids, such as stearicacid; amines of long-chain carboxylic acids, such as stearamide; fattyacid esters; metal salts of long-chain carboxylic acids, such as zincstearate; or polysiloxanes.

Examples of flame retardants suitable for the invention include triarylphosphates, trialkyl phosphates, triaryl or trialkyl phosphatescontaining halogen, melamine, melamine resin, halogenated paraffin, redphosphorus or combinations thereof.

Other aids suitable for the invention include moisture scavengers, suchas molecular sieves; antifoaming agents, such as polydimethylsiloxane;coupling agents, such as monoethylene oxide or organoaminefunctionalized trialkoxysilane or combinations thereof. A coupling agentis particularly preferred for enhancing the binding strength between aresin matrix and a fibrous reinforcement material. A fine filler, forexample, clay or fumed silica, is usually used as a thixotropic agent.

Radical reaction suppressants suitable for the invention includepolymerization inhibitors, polymerization retarders and the like, suchas some phenol, quinine or hindered amine compounds, examples of whichinclude methylhydroquinone, p-methoxyphenol, benzoquinone, polymethylpiperidine derivatives, low valence copper ions, etc.

II. Preparation of Polyurethane Composite Material

In another aspect of the invention, there is provided a process ofpreparing a polyurethane composite material which comprises apolyurethane resin matrix and a reinforcement material, comprising:preparing the polyurethane resin matrix under such reaction conditionsthat a polyurethane composition undergoes addition polymerizationreaction of isocyanate groups and hydroxyl groups and radicalpolymerization reaction simultaneously, wherein the polyurethanecomposition is described above.

In an embodiment of the invention, the polyurethane additionpolymerization (i.e. the addition polymerization of isocyanate group andhydroxyl group) and the radical polymerization occur at the same time.As known to one skilled in the art, tin or amine catalysts may be usedto promote polyurethane addition polymerization; heat or promotors suchas aniline compounds may be used to accelerate radical polymerization;and promoters such as cobalt salts may promote both polyurethaneaddition polymerization and radical polymerization. Hence, one skilledin the art may choose suitable conditions such that a polyurethanecomposition undergoes addition polymerization reaction of isocyanategroups and hydroxyl groups and radical polymerization reactionsimultaneously.

The polyurethane composite material of the invention may be prepared bya vacuum infusion process for polyurethane. The operation of a vacuuminfusion process for polyurethane is well known to those skilled in theart, and is described, for example, in the disclosure of CN 1954995A,the content of which is incorporated herein in its entity by reference.

In the vacuum infusion process, one or more pieces of a core materialare disposed in a mold, wherein the core material is optionally coveredwith a reinforcement material completely or partly. Then, a negativepressure is formed in the mold, such that a polyurethane resin isinfused into the mold. Prior to curing, the polyurethane resin will wetthe reinforcement material completely. The core material will be wettedby the polyurethane resin completely or partly, too. Subsequently,suitable conditions are employed to allow the polyurethane resin toundergo polyurethane addition polymerization reaction and radicalpolymerization reaction simultaneously, such that the polyurethane resinis cured to form a polyurethane resin matrix. In the above vacuuminfusion process, the mold may be a common mold in the art. The mold maybe selected by one skilled in the art according to the desiredproperties and dimensions of the final product. When the vacuum infusionprocess is used to prepare a large article, in order to guarantee asufficient pot-life, the viscosity of the resin shall be kept low enoughto maintain desirable flowability during infusion. If the viscosity ofthe resin is higher than 600 mPa·s, the viscosity will be viewed undulyhigh such that the flowability becomes poor and the resin is notsuitable for the vacuum infusion process.

As used herein, the term “pot-life” is defined as the period of timefrom the point when a polyurethane composition is mixed to the pointwhen the viscosity reaches 600 mPa·s.

As used herein, the term “gel time” means the period of time from thepoint when a polyurethane composition is mixed to the point when thecomposition begins to appear in a gel state. In the invention, the geltime is determined using a gelometer.

The use of a core material in combination with a polyurethane resinmatrix and a reinforcement material facilitates the molding of thecomposite material and the weight reduction of the composite material. Acore material commonly used in the art may be used for the polyurethanecomposite material of the invention, examples of which include but arenot limited to polystyrene foam such as COMPAXX® foam; polyester PETfoam; polyimide PMI foam; polyvinyl chloride foam; metal foams, such asthose available from Mitsubishi Co.; balsa wood; and the like. In anembodiment of the invention, the reinforcement material preferably hasan amount of 1-90 wt. %, more preferably 30-85 wt. %, most preferably50-75 wt. %, based on 100 wt. % by weight of the polyurethane compositematerial.

In some embodiments of the invention, the polyurethane compositioncomprises one or more organic polyols, wherein the organic polyols havea functionality of 1.9-4.5, more preferably 2.6-4.0, still preferably2.8-3.3, and a hydroxyl number of 150-550 mgKOH/g, more preferably250-400 mgKOH/g, still preferably 300-370 mgKOH/g. The polyurethanecomposition is suitable for the polyurethane vacuum infusion process toprepare a polyurethane composite material, wherein the pot-life isfairly long. The polyurethane composite material prepared by thepolyurethane vacuum infusion process has good mechanical properties, andparticularly, it has a high thermal deformation temperature. As such,the problem in the art that the pot-life of the polyurethane compositionand the thermal deformation temperature of the resulting polyurethanecomposite material can not be improved at the same time has been solved.These polyurethane composite materials may be used to manufacture windgenerator blades, wind generator nacelle housings, watercraft propellerblades, hulls, interior and exterior automobile decorative parts,automobile bodies, radomes, machinery structural members, decorativeparts and structural members for architectures and bridges.

The polyurethane composite material of the invention may be prepared bya process selected from compression molding, filament winding, handlay-up moulding, spray lay-up moulding and combinations thereof. SeeChapters 2 and 6-9 in Composite Material Processes And Equipments (LiuXiongya, et al., 1994, Publishing House of Wuhan University ofTechnology) for details about these processes. This literature isincorporated herein in its entity by reference.

In some other embodiments of the invention, the polyurethane compositioncomprises one or more polyether polyols, wherein the polyether polyolshave a functionality of 1.7-6, more preferably 2.5-5.8, still preferably2.7-4.5, and a hydroxyl number of 150-1100 mgKOH/g, more preferably250-550 mgKOH/g, still preferably 300-450 mgKOH/g. The polyurethanecomposition is useful in a compression molding process for preparing apolyurethane composite material which may be used to manufacture fiberreinforcement bars or anchor rods in place of steel bars. The specificproduction process can be found in CN1562618A, CN1587576A, CN103225369A,U.S. Pat. No. 5,650,109A, U.S. Pat. No. 5,851,468A, US2002031664A,WO2008128314A1, and U.S. Pat. No. 5,047,104A which are incorporatedherein in their entity by reference.

The invention will be further illustrated with reference to thefollowing specific examples. However, it is to be appreciated that theseexamples are only intended to illustrate the invention without limitingthe scope of the invention.

EXAMPLES

The test methods in the following examples for which no specificconditions are indicated will be carried out generally underconventional conditions or under those conditions suggested by themanufacturers. All percentages and parts are based on weight unlessotherwise specified.

The starting materials used in the examples are listed as follows:

Desmodur 1511 L: an isocyanate, isocyanate group content 31.4 wt. %,average functionality 2.7, available from Bayer Material ScienceCorporate;

Polyether polyol 1: a polyol having a functionality of 3 and a hydroxylnumber of 470 KOH/g, prepared using glycerin as a starter and propyleneoxide as the main polymerization component;

Polyether polyol 2: a polyol having a functionality of 3 and a hydroxylnumber of 350 KOH/g, prepared using glycerin as a starter and propyleneoxide as the main polymerization component;

Hydroxypropyl methacrylate: available from Hersbit Chemical Co.;

Benzoyl peroxide: available from Aladdin Reagent Co.;

Initiator 925H: available from Syrgis Co.;

BAYLITH L-paste: molecular sieve, available from Shanghai HuanqiuMolecular Sieve Co., Ltd.;

BYK 066 N: a defoaming agent, available from Byk Co.;

H8006 R: a defoaming agent, which is a silicone air release agent,available from Hensin Co.;

The tensile properties of the resin are determined according to ISO527-2;

The curing volume of the resin is determined according to ISO 3521;

HDT is determined according to ISO 75-2.

The gel time is determined as follows: the polyurethane composition isagitated at room temperature in a centrifugal agitator at 2000 rpm for 1minute, and then the gel time is measured using a gelometer. Time iscounted when the agitation is started. The gelometer useful in theinvention may be, for example, GTS-THP available from Paul N. Gardner,Co., USA.

In the following examples, the isocyanate index is defined as follows:

X(%)=([moles of the isocyanate group (NCO group) in component A])/[molesof the isocyanate-reactive group in component B]×100%,

wherein component A refers to the organic isocyanate component, andcomponent B refers to all the other components except for the organicisocyanate component.

Examples 1-3

First, a cast mold was placed in an oven at 160° C. Then, the componentslisted in Table 1 were blended in the specified proportions.Subsequently, the resin was mixed in a centrifugal agitator at 1500 rpmfor 10 minutes. Then, the resin was poured into the mold and allowed tocure at 160° C. for 10 minutes to afford the polyurethane resin matriceof Comparative Examples 1-2 and Examples 1-3.

TABLE 1 Polyurethane compositions and mechanical properties thereofComparative Comparative Examples Formulation Example 1 Example 2 Example1 Example 2 Example 3 Component B Polyether 100 30 50 60 90 polyol 1Hydroxypropyl / 70 50 40 10 methacrylate L-paste 4 4 4 4 4 Benzoyl / 2 22 2 peroxide Component A Desmodur 118 104 108 110 116 1511L Isocyanate105 105 105 105 105 105 index (%) Fraction of / 14.6% 23.8% 28.3% 41.3%polyol in polyurethane composition Fraction of / 34.0% 24.0% 18.9%  4.6%Hydroxypropyl methacrylate in polyurethane composition Reactivity Geltime 80 minutes 410 minutes 270 minutes 211 minutes 120 minutes Pot-life34 minutes 141 minutes 115 minutes  81 minutes  41 minutes Temperature/23 23 23 23 23 ° C. Mechanical Barcol 35 55 53 50 38 properties hardness(Hba) Tensile 3100 / 3900 4200 3300 modulus (MPa) Tensile 80 / 84 95 85strength (MPa) Tensile 5.6 / 3.0 63.9 4.5 elongation at break (%) Volume8.4 11.4 9.4 9 9.3 shrinkage (%)

Comparison between Comparative Examples 1-2 and Examples 1-3 indicatesthat when hydroxypropyl methacrylate is used, the gel time and pot-lifeof the resin is increased remarkably, and the tensile modulus andtensile strength are enhanced greatly too. However, Example 3 shows thatwhen hydroxypropyl methacrylate is too little, pot-life increase is notlong enough. When the polyol comprises 28.3% of the polyurethanecomposition, the tensile strength and modulus of the polyurethanecomposition are maximized, the tensile elongation at break is relativelyhigh, and the volume shrinkage is minimized. In Comparative Example 2,the curing shrinkage is too large, such that the plate prepared from theresin warps and cracks, and no article can be cut therefrom. Therefore,amount of hydroxypropyl methacrylate must not be too high.

Example 4

The isocyanate component was vacuumed at room temperature for 0.1-2 h toexpel bubbles from the starting material. The moisture content in eachpolyol component was controlled below 0.1%, and the polyol component wasvacuumed at room temperature for 0.1-2 h to expel bubbles from thestarting material. Then, the isocyanate component and the polyolcomponent (Index 101) were blended in the proportions listed in Table 2,and 0.5% 925 H, 0.5% BYK 066 N and 0.5% H8006 R (weight percentage basedon the total weight of the isocyanate component and the polyolcomponent) were added. After mixed thoroughly, the resulting mixture wasmonitored. The pot-life (operable time) value was obtained by monitoringthe viscosity variation which was observed by measuring the viscosity ofthe mixture system at intervals. The resulting resin was charged into acast mold, cured at room temperature, and cured at 80° C. for anothertwo hours. The polyurethane resin matrice of Comparative Example 3 andExample 4 were obtained.

TABLE 2 Polyurethane compositions and mechanical properties thereofExamples Comparative Formulation Example 3 Example 4 Component BPolyether polyol 2 100 68 Fraction of polyol in / 36.3 polyurethanecomposition Hydroxypropyl methacrylate / 32 Fraction of Hydroxypropyl /17.0% methacrylate in polyurethane composition 925H / 2 Component ADesmodur 1511L 85 88 (Index) Reactivity Pot-life (min.) 39 87 Gel-time(min.) 86 217 Mechanical Shore D 85 86 properties Tensile modulus (MPa)3100 3200 Tensile strength (MPa) 61 72 Tensile elongation at break 3.44.6 (%) Bend strength (MPa) 103 118 Thermal deformation 61 91temperature (HDT/° C.)

Comparison between Comparative Example 3 and Example 4 indicates thatwhen hydroxypropyl methacrylate is used, the gel time, HDT and pot-lifeof the resin are increased remarkably, and the tensile modulus, tensilestrength and the bend strength are enhanced greatly too. As shown by thecomparison between Comparative Example 3 and Example 4, the polyurethaneresin matrix obtained by addition of hydroxypropyl methacrylate exhibitsbetter comprehensive properties than a conventional polyurethane resin.

Example 5

The polyurethane composite materials in this example were based on thepolyurethane compositions of Comparative Example 3 and Example 4,prepared by the vacuum infusion process and measured for theirproperties.

The operation was conducted on a flat glass plate as follows: a piece ofuniaxial glass fiber cloth (available from SAERTEX Reinforcements(Dongying) Co., uniaxial glass fiber, oriented at 0 degree,14EU970-01190-(width)-100000) was placed on a surface of a flat glassplate spray-coated with a release agent, and then a piece of releasecloth, a fluid-conducting web and a vacuum bag were placed thereon insequence. This device was connected to vacuum at the front, and to theliquid resin at the rear through a fluid-conducting pipe.

The isocyanate component was vacuumed at room temperature for 0.1-2 h toexpel bubbles from the starting material. The moisture content in eachpolyol component was controlled below 0.1%, and the polyol component wasvacuumed at room temperature for 0.1-2 h to expel bubbles from thestarting material. Then, the isocyanate component and the polyolcomponent (Index 1.02) were blended in the proportions listed in Table2, and 0.5% 925 H, 0.5% BYK 066 N and 0.5% H8006 R (weight percentagebased on the total weight of the isocyanate component and the polyolcomponent) were added. After mixed thoroughly, the resulting mixture wasintroduced into the glass fiber cloth in the above device under vacuum.After the glass fiber glass was wetted completely, the whole systemwetted thoroughly by the polyurethane resin was held under vacuumcondition. After cured at room temperature, it was aged at 80° C. foranother hour, and a polyurethane composite material reinforced by glassfiber cloth was obtained. The properties of the resulting polyurethanecomposite materials are shown below.

The properties of the polyurethane composite materials of the inventionare listed in Table 3.

TABLE 3 Properties of polyurethane composite materials Physicalproperties Comparative Example 4 Example 5 Tensile strength (MPa) 8301020 Tensile modulus (MPa) 38000 44200 Tensile elongation at break (%)4.2 7.6

Comparison between Comparative Example 4 and Example 5 indicates thatwhen hydroxypropyl methacrylate is used, the resulting polyurethaneresin matrix can afford a composite material having better mechanicalproperties than a composite material prepared from a prior artpolyurethane resin.

What is claimed is:
 1. A non-foamed polyurethane composite material,comprising a homogeneous polyurethane resin matrix prepared from apolyurethane composition and a reinforcement material, wherein thepolyurethane composition comprises: A) an isocyanate componentcomprising one or more organic polyisocyanates; B) anisocyanate-reactive component comprising: b1) one or more organicpolyols having an amount of 21-60 wt. % based on 100% by weight of thepolyurethane composition; b2) one or more compounds having structure (I)

wherein R₁ is selected from hydrogen, methyl or ethyl; R₂ is selectedfrom alkylene groups having 2-6 carbon atoms, 2,2-bis(4-phenylene)propane, 1,4-bis(methylene) benzene, 1,3-bis(methylene) benzene,1,2-bis(methylene) benzene; n is an integer selected from 1-6; and C) aradical reaction initiator, wherein the polyurethane resin matrix isprepared under such reaction conditions that the polyurethanecomposition undergoes addition polymerization reaction of isocyanategroups and hydroxyl groups and radical polymerization reactionsimultaneously, and wherein the polyurethane composite is prepared by aprocess selected from compression molding, hand lay-up moulding, orfilament winding.
 2. The polyurethane composite material according toclaim 1, wherein the component b1) is selected from one or morepolyether polyols.
 3. The polyurethane composite material according toclaim 1, wherein the component b2) is selected from the group consistingof hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutylmethacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate,hydroxybutyl acrylate and combinations thereof.
 4. The polyurethanecomposite material according to claim 1, wherein the organic polyolshave a functionality of 1.7-6 and a hydroxyl number of 150 to 1100 mgKOH/g.
 5. The polyurethane composite material according to claim 4,wherein the polyurethane composite material is prepared by vacuuminfusion process.
 6. The polyurethane composite material according toclaim 1, wherein the reinforcement material is selected from the groupconsisting of glass fibers, carbon nanotubes, carbon fibers, polyesterfibers, natural fibers, aramid fibers, nylon fibers, basalt fibers,boron fibers, silicon carbide fibers, asbestos fibers, whiskers, metalfibers and combinations thereof.
 7. A process of preparing a non-foamedpolyurethane composite material which comprises a homogeneouspolyurethane resin matrix and a reinforcement material, comprising:preparing the polyurethane resin matrix under such reaction conditionsthat a polyurethane composition undergoes addition polymerizationreaction of isocyanate groups and hydroxyl groups and radicalpolymerization reaction simultaneously, wherein the polyurethanecomposition comprises: A) an isocyanate component comprising one or moreorganic polyisocyanates; B) an isocyanate-reactive component comprising:b1) one or more organic polyols having an amount of 21-60 wt. % based on100% by weight of the polyurethane composition; b2) one or morecompounds having structure (I)

wherein R₁ is selected from hydrogen, methyl or ethyl; R₂ is selectedfrom alkylene groups having 2-6 carbon atoms, 2,2-bis(4-phenylene)propane, 1,4-bis(methylene) benzene, 1,3-bis(methylene) benzene,1,2-bis(methylene) benzene; n is an integer selected from 1-6; and C) aradical reaction initiator.
 8. The process of preparing a polyurethanecomposite material according to claim 7, wherein the component b1) isselected from one or more polyether polyols.
 9. The process of preparinga polyurethane composite material according to claim 7, wherein thecomponent b2) is selected from the group consisting of hydroxyethylmethacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate,hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate andcombinations thereof.
 10. The process of preparing a polyurethanecomposite material according to claim 7, wherein the organic polyolshave a functionality of 1.7-6 and a hydroxyl number of 150 to 1100 mgKOH/g.
 11. The process of preparing a polyurethane composite materialaccording to claim 10, wherein the polyurethane composite material isprepared by a process selected from compression molding, filamentwinding, hand lay-up moulding, spray lay-up moulding and combinationsthereof.
 12. The process of preparing a polyurethane composite materialaccording to claim 11, wherein the polyurethane composite material isprepared by vacuum infusion process.
 13. The process of preparing apolyurethane composite material according to claim 7, wherein thereinforcement material is selected from the group consisting of glassfibers, carbon fibers, polyester fibers, natural fibers, aramid fibers,nylon fibers, basalt fibers, boron fibers, silicon carbide fibers,asbestos fibers, whiskers, metal fibers and combinations thereof.
 14. Anon-foamed polyurethane composite material, comprising a homogeneouspolyurethane resin matrix prepared from a polyurethane composition and areinforcement material, wherein the polyurethane composition comprises:A) an isocyanate component comprising one or more organicpolyisocyanates; B) an isocyanate-reactive component comprising: b1) oneor more organic polyols having an amount of 21-60 wt. % based on 100% byweight of the polyurethane composition; b2) one or more compounds havingstructure (I)

wherein R₁ is selected from hydrogen, methyl or ethyl; R₂ is selectedfrom alkylene groups having 2-6 carbon atoms, 2,2-bis(4-phenylene)propane, 1,4-bis(methylene) benzene, 1,3-bis(methylene) benzene,1,2-bis(methylene) benzene; n is an integer selected from 1-6; and C) aradical reaction initiator, wherein the polyurethane resin matrix isprepared under such reaction conditions that the polyurethanecomposition undergoes addition polymerization reaction of isocyanategroups and hydroxyl groups and radical polymerization reactionsimultaneously, and wherein the polyurethane composite is prepared byvacuum infusion process.
 15. The polyurethane composite materialaccording to claim 14, wherein the component b1) is selected from one ormore polyether polyols.
 16. The polyurethane composite materialaccording to claim 14, wherein the component b2) is selected from thegroup consisting of hydroxyethyl methacrylate, hydroxypropylmethacrylate, hydroxybutyl methacrylate, hydroxyethyl acrylate,hydroxypropyl acrylate, hydroxybutyl acrylate and combinations thereof.17. The polyurethane composite material according to claim 14, whereinthe organic polyols have a functionality of 1.7-6 and a hydroxyl numberof 150 to 1100 mg KOH/g.
 18. The polyurethane composite materialaccording to claim 14, wherein the reinforcement material is selectedfrom the group consisting of glass fibers, carbon nanotubes, carbonfibers, polyester fibers, natural fibers, aramid fibers, nylon fibers,basalt fibers, boron fibers, silicon carbide fibers, asbestos fibers,whiskers, metal fibers and combinations thereof.
 19. A non-foamedpolyurethane composite material, comprising a homogeneous polyurethaneresin matrix prepared from a polyurethane composition and areinforcement material, wherein the polyurethane composition comprises:A) an isocyanate component comprising one or more organicpolyisocyanates; B) an isocyanate-reactive component comprising: b1) oneor more organic polyols having an amount of 21-60 wt. % based on 100% byweight of the polyurethane composition; b2) one or more compounds havingstructure (I)

wherein R₁ is selected from hydrogen, methyl or ethyl; R₂ is selectedfrom alkylene groups having 2-6 carbon atoms, 2,2-bis(4-phenylene)propane, 1,4-bis(methylene) benzene, 1,3-bis(methylene) benzene,1,2-bis(methylene) benzene; n is an integer selected from 1-6; and C) aradical reaction initiator, wherein the polyurethane resin matrix isprepared under such reaction conditions that the polyurethanecomposition undergoes addition polymerization reaction of isocyanategroups and hydroxyl groups and radical polymerization reactionsimultaneously, and wherein the polyurethane composite is prepared by aprocess comprising spray lay-up moulding.
 20. The polyurethane compositematerial according to claim 19, wherein the component b1) is selectedfrom one or more polyether polyols.
 21. The polyurethane compositematerial according to claim 19, wherein the component b2) is selectedfrom the group consisting of hydroxyethyl methacrylate, hydroxypropylmethacrylate, hydroxybutyl methacrylate, hydroxyethyl acrylate,hydroxypropyl acrylate, hydroxybutyl acrylate and combinations thereof.22. The polyurethane composite material according to claim 19, whereinthe organic polyols have a functionality of 1.7-6 and a hydroxyl numberof 150 to 1100 mg KOH/g.
 23. The polyurethane composite materialaccording to claim 19, wherein the reinforcement material is selectedfrom the group consisting of glass fibers, carbon nanotubes, carbonfibers, polyester fibers, natural fibers, aramid fibers, nylon fibers,basalt fibers, boron fibers, silicon carbide fibers, asbestos fibers,whiskers, metal fibers and combinations thereof.